Conventionally, normal information of an object is acquired from polarization images of a plurality of polarization directions. For example, in Non-Patent Literature 1 and Non-Patent Literature 2, normal information is computed by applying polarization images of a plurality of polarization directions to a model expression. Also, recognition or the like of an object is performed using the polarization images. For example, in Patent Literature 1, an illuminating means is arranged so that illumination light serves as p-polarized light to a predetermined reference surface and illuminates an object. Further, in Patent Literature 1, an intensity of light of each polarized light component is measured by separating reflected light from the reference surface into s-polarized light and p-polarized light and the object is identified on the basis of an obtained measurement result of the intensity of light while the object to be measured moves along the reference surface.